Mechanisms of endothelin-1 mRNA and peptides induction by TGF-beta and TPA in MDCK cells.

Mechanisms of prepro-ET-1 mRNA expression and mature endothelin-1 (ET-1) peptide secretion in MDCK cells (dog collecting duct origin) were investigated. MDCK cells constitutively expressed prepro-ET-1 mRNA (approximately 2.3 kb).

Uterine artery ligation in the maternal rat alters fetal tissue glucose utilization.

We studied the effects of maternal uterine artery ligation on fetal rat tissue glucose utilization (GU). Unilateral uterine artery ligations were performed on the 19th d of gestation (term 21.5 d) and 2-[3H]deoxy-D-glucose was used to measure GU of placenta, liver, brain, muscle, kidney, and heart from fetuses in the ligated (IUGR) and nonligated (control) uterine horns 24 and 48 h after the procedure.

Distinctive regulation of the functional linkage between the human cation-independent mannose 6-phosphate receptor and GTP-binding proteins by insulin-like growth factor II and mannose 6-phosphate.

The rat insulin-like growth factor II (IGF-II) receptor develops transmembrane signaling functions by directly coupling to a guanine nucleotide-binding protein (G protein) having a 40-kDa alpha subunit, Gi-2, whereas recent studies have indicated that the IGF-II receptor is a molecule identical to the cation-independent mannose 6-phosphate receptor (CI-MPR), a receptor implicated in lysosomal enzyme sorting. In this study, by using vesicles reconstituted with the clonal human CI-MPR and G proteins, we indicated that the CI-MPR could stimulate guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) binding and GTPase activities of Gi proteins in response to IGF-II. The stimulatory effect of IGF-II on Gi-2 depended on the reconstituted amount of the CI-MPR; it could not be found in vesicles reconstituted with Gi-2 alone; and it was also observed on Gi-1 reconstituted with the CI-MPR in phospholipid vesicles.

Insulin-like growth factor-I stimulates diacylglycerol production via multiple pathways in Balb/c 3T3 cells.

We previously reported that insulin-like growth factor-I (IGF-I) induced sustained calcium cycling across the plasma membrane in primed competent Balb/c 3T3 cells (Kojima, I., Matsunaga, H., Kurokawa, K.

Amniotic fluid insulin concentration as a predictor of obesity.

Longitudinal correlations were obtained between amniotic fluid insulin concentration at 32 to 38 weeks' gestation and anthropometric characteristics at the age of 6 years in 56 children of diabetic mothers. The prospective studies indicated that at the age of 6 years, as at birth, the greatest increase in weight in relation to height (relative obesity) was seen in children who experienced the greatest exposures to insulin in the uterus (as judged by amniotic fluid insulin concentration). Significant correlations between amniotic fluid insulin and relative obesity at the age of 6 years were found after adjustment for maternal obesity and macrosomia at birth.

Circulating levels of insulin-like growth factor binding protein-1 (IGFBP-1) and hepatic mRNA are increased in the small for gestational age (SGA) fetal rat.

Insulin-like growth factors (IGFs) circulate in association with a family of specific binding proteins (BPs). Recently, we reported that circulating levels of IGFBP-1 and IGFBP-2 are increased in streptozotocin-diabetic adult rats and are differentially regulated in accordance with insulin and metabolic status. Since IGF BPs appear to be important modulators of IGF bioactivity in post-natal life, we asked whether serum levels of IGF BPs also might be altered in utero when the delivery of maternal nutrients is restricted and fetal growth is impaired.

Systemic and regional hemodynamics in patients with salt-sensitive hypertension.

Twenty-two patients with normal plasma renin and essential hypertension were classified as "salt-sensitive" (SS) (n = 9) or "non-salt-sensitive" (NSS) (n = 13) from an increase in mean blood pressure with changes in sodium intake from 25 to 250 meq/day. With the high sodium diet, the SS patients gained more weight (p less than 0.05), retained more sodium (p less than 0.

Phasic plasma atrial natriuretic polypeptide changes in DOCA-salt hypertensive rats.

We determined plasma and cardiac immunoreactive atrial natriuretic polypeptide (ir-ANP) levels in rats treated with deoxycorticosterone acetate (DOCA) and sodium chloride for 1, 7, and 28 days. Systolic blood pressure of DOCA-salt rats began to increase from the 7th day and reached 191 +/- 7 mmHg at the 28th day. One day after treatment with DOCA-salt, plasma levels of ir-ANP were increased compared to that of control rats.

A simple structure encodes G protein-activating function of the IGF-II/mannose 6-phosphate receptor.

The insulin-like growth factor-II/mannose 6-phosphate receptor (IGF-II/man6PR) can directly interact with and activate Gi-2, a GTP binding protein (G protein). We found that the segment of residues 2410-2423 in the human IGF-II/man6PR activates Gi-2 in a manner similar to G-coupled receptors. We observed a hierarchy of the segment action when tested on various G proteins, with an order of Gi-2 greater than Gi-1 approximately Gi-3 greater than Go.

Attenuated vasodilator responses to Mg2+ in young patients with borderline hypertension.

Limb vascular responses to magnesium (Mg2+) and potassium (K+) ions were studied in 19 young patients with borderline hypertension (BHT) and compared with those of 22 age-matched normotensive subjects (NT) by measuring the forearm blood flow response to intra-arterial infusion of magnesium sulfate and potassium chloride using venous occlusion plethysmography. Percent decrements of forearm vascular resistance with Mg2+ infusions were significantly less in BHT subjects than in NT (-37.2 +/- 4.

Interrelationship between serum muscle enzymes and a low T3 in anorexia nervosa.

To determine the interrelationship between muscle dysfunction and a low T3 state, both seen in anorexia nervosa, we studied the relationship between the degree of muscle involvement, as assessed by the circulating concentration of the three muscle indicators (CPK, GOT and LDH), and serum T3 in thirty-three patients when they were admitted to the hospital. We also studied the malnutritional state, as assessed by their body weight or serum GH, serum potassium and the degree of hyperactivity exhibited. Additionally, another twelve patients were studied in order to explore the mounding phenomenon which is typically elicited in hypothyroidism.

In vitro responsiveness of aldosterone-producing adenoma to angiotensin II, K and ACTH.

In vitro responsiveness to various stimulators of aldosterone secretion was studied in a perifusion system using slices obtained from three aldosterone-producing adenomas (APAs), three adjacent nontumorous glands and three normal adrenal glands. All three APA tissues responded to angiotensin II, K and ACTH in vitro. Angiotensin II (10 nM), K (12 mM) and ACTH (10 nM) caused more than a 2-fold increase in aldosterone secretion.

Synergistic action of activin A and hexamethylene bisacetamide in differentiation of murine erythroleukemia cells.

Activin A, a peptide homologous to transforming growth factor beta, induced erythroid differentiation of murine erythroleukemia cells in a dose-dependent manner, as judged by the proportion of benzidine-positive cells. The extent of differentiation induced by activin A depended on the cell density in the initial inoculum; the percentage of benzidine-positive cells markedly decreased at an increasing cell density. In contrast, the hexamethylene bisacetamide (HMBA)-induced differentiation was affected only to a little extent by the cell density.

Studies on the cell-cycle dependency of the actions of insulin-like growth factor-I in Balb/c 3T3 cells.

The present study was conducted to determine the cell-cycle dependency of various actions of IGF-I in Balb/c 3T3 cells. When autophosphorylation of the IGF-I receptor was determined in [32P]-labelled cells, IGF-I increased radioactivity in a 100 K-Da phosphoprotein, presumably beta-subunit of the IGF-I receptor, both in quiescent and in primed competent cells. Likewise, IGF-I stimulated uptake of [3H]deoxyglucose independent of the cell cycle.

Mechanism of prostaglandin E2-induced glucose production in rat hepatocytes.

Effects of prostaglandin E2 (PGE2) on glycogenolysis were examined in rat hepatocytes. In a batch incubation system using isolated hepatocytes, PGE2 increased glucose output dose-dependently. The glycogenolytic effect of PGE2 was detected at a concentration of 10(-11) M, and 10(-8) M PGE2 elicited the maximum glucose output, which was equal to that by glucagon.

Insulin-like growth factor-II/mannose 6-phosphate receptor is incapable of activating GTP-binding proteins in response to mannose 6-phosphate, but capable in response to insulin-like growth factor-II.

We previously reported that insulin-like growth factor-II (IGF-II) stimulates both calcium influx and DNA synthesis by acting on the cell surface IGF-II receptor (IGF-IIR) in a manner sensitive to pertussis toxin, and recently demonstrated that IGF-II binding to the IGF-IIR gives rise to functional changes of purified Gi-2, a GTP-binding protein (G protein) in phospholipid vesicles as well as in broken cell membranes. On the other hand, a variety of evidence indicates that the IGF-IIR binds mannose 6-phosphate (man6P) with high affinity probably at a receptor extracellular region different from the IGF-II-binding site. In the present study, we examined whether man6P stimulation of the IGF-IIR evokes the activation of Gi-2 in phospholipid vesicles and in native cell membranes.

Inducible gene expression of activin A/erythroid differentiation factor in HL-60 cells.

Treatment of HL-60 cells with 12-O-tetradecanoyl-phorbol 13-acetate (TPA) for 48 h induced expression of mRNA of beta A chain of activin A/erythroid differentiation factor. Under the same condition, interferon-gamma caused a slight increase in beta A chain mRNA, whereas 1 alpha, 25-dihydroxyvitamin D3, dimethylsulfoxide and all-trans-retinoic acid failed to induce this mRNA in HL-60 cells. Furthermore, 4 h-treatment with TPA or lipopolysaccharide (LPS) induced a marked increase in beta A chain mRNA levels in interferon-gamma-pretreated HL-60 cells.

Difference in sensitivity to glucagon action in three different rat liver systems.

We compared sensitivity to glucagon in three different rat liver systems. In perfused liver, half-maximal response of glycogenolysis was obtained by 5 x 10(-11) mol/L glucagon. In contrast, half-maximal response was obtained by 10(-9) mol/L glucagon in batch incubation of isolated hepatocytes.

Isolation and characterization of proteoglycans synthesized by mouse osteoblastic cells in culture during the mineralization process.

Proteoglycans in mineralized (0.5 M-EDTA/4 M-guanidinium chloride-extractable) and non-mineralized (4 M-guanidinium chloride-extractable) matrices synthesized by a mouse osteoblastic-cell line MC3T3-E1 were characterized at different phases of mineralization in vitro. Cell cultures were labelled with [35S]sulphate and either [3H]glucosamine or 3H-labelled amino acids.

Intrauterine growth retardation: altered hepatic energy and redox states in the fetal rat.

We determined the extent to which ligating both maternal uterine arteries affects fetal hepatic energy and redox states in the fetal rat. Bilateral maternal uterine artery ligation on d 18 of the rat's 21.5-d gestation significantly inhibits fetal growth; sham surgery limits growth to a lesser extent.